Black sulfur dye.



UNITED STATES PATENT QFEICE.

WILLIAM H. CLAUS, ALFRED REE, AND LEON MARGHLEWSKI, OF MAN- CHESTER, ENGLAND.

BLACK SULFUR DYE.

SPECIFICATION forming part of Letters Patent No. 639,806, dated December 26, 1899.

Application filed August 14, 1899. Serlal No. 727,172. (No specimens.)

ter can be obtained by heating with sulfur and an alkaline sulfid dinitro-ortho-hydroxydiphenylamin of the constitution:

NO NH No, OH

The following will serve as an example of the invention: Five parts of dinitro-orthohydroxydiphenylamin, ten parts of sulfur, thirty parts of crystallized sodium sulfid,and ten parts of water are heated for several hours at to centigrade and the temperature is then gradually raised to centigrade, at which temperature the melt is kept for about three hours, when it is finally raised to to centigrade. There is thus obtained a black mass, which dissolves in water with a greenish-blue color and which can be used directly for dyeing. It gives greenish shades of black on unmordanted cotton, which may be further developed by aging or by an after treatment with bichromates or with copper salts in presence of acetic acid, or with a mixture of these salts. The shades obtained are extremely fast to light, acids, and alkalies. Our discovery that certain compounds in which the OH group is in ortho position to an NH group give on heating with sulfur and alkaline sulfids black coloring-matters of exceptional fastness contradicts the hitherto prevalent belief that only compounds may be used for this purpose which contain an hydroxy group in para position to an NH group. (Compare Revue Gnrale des llfatieres O'olorcmtes, Vol. III, No. 30, p. 214.)

Having'now described our invention, what we claim as new is The process for the production of black coloring-matter capable of directly dyeing cotton fiber, which consists in heating dinitroorthohydroxydiphenylamin having the constitution --NO, on with sulfur and an alkaline sulfid, substantially as described.

In witness whereof we subscribe our signatures in presence of two witnesses.

WILLIAM H. OLAUS. ALFRED REE. LEON MAROHLEWSKI.

Witnesses:

WILLIAM GEo. HEYs, ARTHUR MILLWARD. 

